1. Theory
Activated carbon is made of wood, coal, fruit shell and other carbon-containing substances activated under high temperature and hypoxia conditions. It has a large number of micropores and a huge specific surface area, usually the surface area of 1 gram of activated carbon can reaches to 5001500 square meters, so it has a strong physical adsorption capacity, can effectively adsorb organic pollutants in wastewater. In addition, some oxygen-containing functional groups, such as carboxyl group (-COOH), hydroxyl group (-Oh) and carbonyl group, are formed on the amorphous part of activated carbon surface in the activation process. These groups enable the activated carbon to have the properties of chemical adsorption, catalytic oxidation and reduction, and can effectively remove some metal ions from wastewater. Activated carbon has a strong adsorption effect, can absorb the tiny particles in industrial wastewater, remove the precipitation, to achieve the purpose of wastewater treatment. Due to the porous structure of activated carbon, a large number of tiny holes are formed on its surface. The diameter of these holes is generally in a very small nanometer order of magnitude, which makes the large relative surface area of activated carbon and huge adsorption of fine particles outside.
In addition to the activated carbon into the industrial wastewater for independent adsorption, can also use hot air method in the adsorption process for activated carbon to provide continuous oxygen, so that the adsorption capacity of activated carbon in ventilation and heating conditions will gradually strengthen, the effect of the sewage treatment is more obvious.
2. The advantages of activated carbon adsorption for industrial wastewater treatment
① Good and relatively stable treatment effect
② The resistance of microorganisms to organic poisons and heavy metals was improved;
③ Cohesive carbon bodies and microorganisms were produced to form solid and dense sludge, which improved the operating conditions of activated sludge process;
③ Activated carbon can adsorb surface active substances and solve the foam problem in the aeration tank
⑤ It can be used to treat wastewater with complex composition, variable concentration and water quantity;
⑥ Low cost of powder carbon.
Activated carbon can not only physically adsorb a lot of insoluble harmful substances, but also effectively adsorb the harmful ions in the ion state. It has the advantages of both physical and chemical treatment methods. In addition, the its efficiency and quality in treatment of industrial wastewater are particularly high. Activated carbon has a large relative surface area due to its porous structure, which gives it high adsorption capacity. At the same time, its carbon chain structure makes it very rigid, which enables the activated carbon to maintain its shape and structure in the use process, and effectively play the adsorption role.
Activated carbon adsorption method has the advantages of physical method processing waste water, free of mercury and chromium in waste water directly on the toxic heavy metal ions and small impurities such as adsorption, supplement add additional chemical agents, this to a certain extent, reduce the cost of industrial wastewater treatment, and avoid the dropping chemical fertilizer could damage. In addition to the advantages mentioned above, the low manufacturing cost of activated carbon is also the key point for people to choose it to treat industrial wastewater. Activated carbon comes from organic waste in life, and after simple carbonization and gas treatment, it becomes the activated carbon for industrial use. In the process of treating wastewater with activated carbon, the structure and properties of activated carbon have not changed, which makes it possible to recycle activated carbon. Through simple washing with water and drying with detergent, activated carbon can be used to treat wastewater again. This method of industrial wastewater treatment with low cost and good effect has been used by many factorie.
